Multiple-input Multiple-output (MIMO) with relay nodes

ABSTRACT

A method for providing multiple-input multiple-output (MIMO) feedback information and configuration information. The method includes transporting the MIMO feedback information, configuration information, or both over an uplink relay link using higher layer signaling. Also included is a method for providing uplink data transmission over an access link. The method includes transporting the uplink data over an uplink access link using orthogonal frequency-division multiplexing access (OFDMA). Also included is a relay node comprising a processor configured to promote transmitting MIMO feedback information, configuration information, or both over an uplink relay link using higher layer signaling. Also included is a user agent (UA) comprising a processor configured to promote transmitting uplink data over an uplink access link using OFDMA.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application and claims priority to co-pending U.S.patent application Ser. No. 12/340,432 filed Dec. 19, 2008, by Yi Yu, etal., entitled “Multiple-Input Multiple-Output (MIMO) With Relay Nodes,”which is incorporated herein by reference as if reproduced in itsentirety.

BACKGROUND

As used herein, the terms “user agent” and “UA” might in some casesrefer to mobile devices such as mobile telephones, personal digitalassistants, handheld or laptop computers, and similar devices that havetelecommunications capabilities. Such a UA might consist of a UA and itsassociated removable memory module, such as but not limited to aUniversal Integrated Circuit Card (UICC) that includes a SubscriberIdentity Module (SIM) application, a Universal Subscriber IdentityModule (USIM) application, or a Removable User Identity Module (R-UIM)application. Alternatively, such a UA might consist of the device itselfwithout such a module. In other cases, the term “UA” might refer todevices that have similar capabilities but that are not transportable,such as desktop computers, set-top boxes, or network appliances. Theterm “UA” can also refer to any hardware or software component that canterminate a communication session for a user. Also, the terms “useragent,” “UA,” “user equipment,” “UE,” “user device” and “user node”might be used synonymously herein.

As telecommunications technology has evolved, more advanced networkaccess equipment has been introduced that can provide services that werenot possible previously. This network access equipment might includesystems and devices that are improvements of the equivalent equipment ina traditional wireless telecommunications system. Such advanced or nextgeneration equipment may be included in evolving wireless communicationsstandards, such as long-term evolution (LTE). For example, an LTE systemmight include an enhanced node B (eNB), a wireless access point, or asimilar component rather than a traditional base station. As usedherein, the term “access node” will refer to any component of thewireless network, such as a traditional base station, a wireless accesspoint, or an LTE eNB, that creates a geographical area of reception andtransmission coverage allowing a UA or a relay node to access othercomponents in a telecommunications system. In this document, the term“access node” and “access device” may be used interchangeably, but it isunderstood that an access node may comprise a plurality of hardware andsoftware.

The term “access node” does not refer to a “relay node,” which is acomponent in a wireless network that is configured to extend or enhancethe coverage created by an access node or another relay node. The accessnode and relay node are both radio components that may be present in awireless communications network, and the terms “component” and “networknode” may refer to an access node or relay node. It is understood that acomponent might operate as an access node or a relay node depending onits configuration and placement. However, a component is called a “relaynode” only if it requires the wireless coverage of an access node toaccess other components in a wireless communications system.Additionally, two or more relay nodes may used serially to extend orenhance coverage created by an access node.

An LTE system can include protocols such as a Radio Resource Control(RRC) protocol, which is responsible for the assignment, configuration,and release of radio resources between a UA and a network node or otherLTE equipment. The RRC protocol is described in detail in the ThirdGeneration Partnership Project (3GPP) Technical Specification (TS)36.331. According to the RRC protocol, the two basic RRC modes for a UAare defined as “idle mode” and “connected mode.” During the connectedmode or state, the UA may exchange signals with the network and performother related operations, while during the idle mode or state, the UAmay shut down at least some of its connected mode operations. Idle andconnected mode behaviors are described in detail in 3GPP TS 36.304 andTS 36.331.

The signals that carry data between UAs, relay nodes, and access nodescan have frequency, time, and coding parameters and othercharacteristics that might be specified by a network node. A connectionbetween any of these elements that has a specific set of suchcharacteristics can be referred to as a resource. The terms “resource,”“communications connection,” “channel,” and “communications link” mightbe used synonymously herein. A network node typically establishes adifferent resource for each UA or other network node with which it iscommunicating at any particular time.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a diagram illustrating a wireless communication system using arelay node, according to an embodiment of the disclosure.

FIG. 2 is a block diagram of a method for establishing an uplink relaylink according to an embodiment of the disclosure.

FIG. 3 is a block diagram of a method for establishing an uplink accesslink according to an embodiment of the disclosure.

FIG. 4 illustrates a processor and related components suitable forimplementing the several embodiments of the present disclosure.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments of the present disclosure areprovided below, the disclosed systems and/or methods may be implementedusing any number of techniques, whether currently known or in existence.The disclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, includingthe exemplary designs and implementations illustrated and describedherein, but may be modified within the scope of the appended claimsalong with their full scope of equivalents.

In wireless communication networks, such as LTE, Multiple-InputMultiple-Output (MIMO) techniques may be used to establish downlinksbetween the network nodes and the UAs and to improve or increase thesystem capacity. For instance, using the MIMO techniques multiple datastreams can be transported at about the same time, at about the samefrequency, or both. Some close-loop MIMO techniques, includingbeamforming and spatial multiplexing, require feedback information, suchas a precoding matrix indicator (PMI), rank indication (RI), and channelquality indicator (CQI), and other configuration information. Such MIMOrelated information may be transported over the links between thenetwork components. In the presence of stationary or fixed relay nodesin the network, the access node may exchange the MIMO relatedinformation more efficiently with the fixed relay nodes in comparison tomobile relay nodes or roaming UAs. However, the close-loop MIMOinformation can be substantially large and lower layer signaling, suchas layer 1 signaling, may not be efficient for transporting suchinformation over the relay link.

Disclosed herein is a system and method for transporting MIMO feedbackinformation, as well as other configuration information using a relaylink between a relay node and an access node. Specifically, the feedbackand configuration information may be transported via an uplink over therelay link using higher layer signaling. As such, the feedbackinformation may be transported with higher accuracy, upon demand, and athigher modulation levels or rates.

The wireless communication networks may also use other techniques, suchas Orthogonal Frequency-Division Multiplexing (OFDM) techniques, toestablish downlinks between the network nodes and the UAs. In OFDM, datais divided over a plurality of subcarriers or resources and modulated atlower rates to improve communications and resource allocation. Incurrent networks, single carrier based techniques are used instead ofOFDM to establish uplinks between the UAs and the network nodes.However, in the presence of relay nodes in the network, radio conditionsbetween the relay nodes and the UAs may be suitable for using OFDM forthe uplinks. For instance, the distances between the relay nodes and theUAs may be relatively small in comparison to the distances between theaccess nodes and the UAs and can promote higher signal-to-interferenceratios (SINRs), which can be suitable for using OFDM to establishuplinks over the access links between the UAs and the relay nodes.

Also disclosed is a system and method for transporting communicationsdata using an access link between the relay link and a UA. Specifically,the uplink data may be transported via an uplink over the access linkusing OFDM access (OFDMA), which may provide discontinuous resourceallocation and increased efficiency. To support the OFDMA discontinuousresource allocation, a bitmap of the assigned resource blocks (RBs) forthe uplink grant, or a bitmap of the assigned sets of continuous RBs,may be transported over a physical downlink control channel (PDCCH).Alternatively, the first RB and the last RB for each set of continuousRBs may be transported over the PDCCH. In other embodiments, the PDCCHdownlink control information (DCI) formats 1, 1A, 2, or 2A, specified inthe 3GPP TS 36.212, may be used instead to signal the uplink grant.

FIG. 1 is a diagram illustrating a wireless communication system 100using a relay node 102, according to an embodiment of the disclosure.Generally, the present disclosure relates to the use of relay nodes inwireless communications networks. Examples of wireless communicationnetworks include LTE or LTE-Advanced (LTE-A) networks, and all of thedisclosed and claimed embodiments could be implemented in an LTE-Anetwork. The relay node 102 can amplify or repeat a signal received froma UA 110 and cause the modified signal to be received at an access node106. In some implementations of a relay node 102, the relay node 102receives a signal with data from the UA 110 and then generates a newsignal to transmit the data to the access node 106. The relay node 102can also receive data from the access node 106 and deliver the data tothe UA 110. The relay node 102 might be placed near the edges of a cellso that the UA 110 can communicate with the relay node 102 rather thancommunicating directly with the access node 106 for that cell.

In radio systems, a cell is a geographical area of reception andtransmission coverage. Cells can overlap with each other. In the typicalexample, there is one access node associated with each cell. The size ofa cell is determined by factors such as frequency band, power level, andchannel conditions. Relay nodes, such as relay node 102, can be used toenhance coverage within or near a cell, or to extend the size ofcoverage of a cell. Additionally, the use of a relay node 102 canenhance throughput of a signal within a cell because the UA 110 canaccess the relay node 102 at a higher data rate or a lower powertransmission than the UA 110 might use when communicating directly withthe access node 106 for that cell. Transmission at a higher data ratecreates higher spectrum efficiency, and lower power benefits the UA 110by consuming less battery power.

Relay nodes, generally, can be divided into three types: layer one relaynodes, layer two relay nodes, and layer three relay nodes. A layer onerelay node is essentially a repeater that can retransmit a transmissionwithout any modification other than amplification and slight delay. Alayer two relay node can decode a transmission that it receives,re-encode the result of the decoding, and then transmit the re-encodeddata. A layer three relay node can have full radio resource controlcapabilities and can thus function similarly to an access node. Theradio resource control protocols used by a relay node may be the same asthose used by an access node, and the relay node may have a unique cellidentity typically used by an access node. For the purpose of thisdisclosure, a relay node is distinguished from an access node by thefact that it requires the presence of at least one access node (and thecell associated with that access node) to access other components in atelecommunications system. The illustrative embodiments are primarilyconcerned with layer two or layer three relay nodes. Therefore, as usedherein, the term “relay node” will not refer to layer one relay nodes,unless specifically stated otherwise.

In communication system 100, the links that allow wireless communicationcan be said to be of three distinct types. First, when the UA 110 iscommunicating with the access node 106 via the relay node 102, thecommunication link between the UA 110 and the relay node 102 is said tooccur over an access link 108. Second, the communication between therelay node 102 and the access node 106 is said to occur over a relaylink 104. Third, communication that passes directly between the UA 110and the access node 106 without passing through the relay node 102 issaid to occur over a direct link 112. The terms “access link,” “relaylink,” and “direct link” are used in this document according to themeaning described by FIG. 1.

In an embodiment, the relay node 102 may provide the MIMO feedbackinformation, configuration information, or both to the access node 106via the relay link 104. Specifically, the relay node 102 may establishan uplink with the access node 106 using higher layer signaling, whichmay be a non-physical layer (non-PHY) signaling, such as RRC signaling,layer 1/2 signaling, layer 3 signaling, or Medium Access Control (MAC)based signaling. For example, the PMI, RI, CQI, or combinations thereofmay be forwarded using the higher layer signaling between the relay node102 and the access node 106. In some embodiments, the relay node 102 andthe access node 106 are not mobile. As such, the channel between therelay node 102 and the access node 106 is relatively stable or slowlyvarying. Typically, the MIMO feedback information may not be requiredfrequently on the relay link, and hence the higher layer signaling maybe used to forward such information when necessary or upon demand.Further, using higher layer signaling may reduce the amount of allocatedresources for the physical layer signaling, for example, the PUCCH,which is typically limited in a system.

Since, the feedback and control information is not transportedfrequently, more data may be transported at each instance of higherlayer signaling without using or sacrificing substantial networkcapacity or bandwidth. For instance, larger and more accurate channelestimation or precoding matrices may be forwarded, which may enhance theperformance of the close-loop MIMO scheme on the relay link. In anembodiment, instead of forwarding PMI or CQI index tables with limitedbit size, larger tables may be sent to reference more values. In someembodiments, the PMI or CQI values or precoding weight values may besent directly, for instance in a floating point format.

For instance, when the access node 106 receives higher layer signaling,such as RRC signaling including a floating point format precoding weightvalue, the higher layer (e.g. RRC) may forward the precoding weightvalues to the physical layer. Hence, the physical layer may directlyapply the precoding weight values for MIMO transmissions without anytable look-up procedures. Currently, the access node 106 receives aplurality of precoding indices, which may be a small set of indices, viathe physical layer signaling. The access node 106 uses the precodingindices to obtain the precoding weight values for MIMO transmissionsfrom a pre-defined table stored in the access node 106 or somewhere inthe network. This current approach reduces the signaling overhead butdegrades the accuracy of the signaling information.

In some embodiments, the downlink or uplink data over the relay link maybe modulated at higher rates in comparison to lower order modulation toimprove transmission efficiency. For instance, the downlink or uplinkdata over the relay link may be modulated using 256 quadrature amplitudemodulation (QAM) or higher order modulations instead of using 64 QAM.

In an embodiment, the access node 106 may forward some MIMOconfiguration information or other network configuration information tothe relay node 102, via the relay link 104, or to the UA 110 via thedirect link 112. Specifically, the access node 106 may establish adownlink with the relay node 102 or the UA 110 using higher layersignaling. As such, the configuration information may be transportedupon demand, with increased accuracy, and without allocating additionalresources for the PDCCH.

In an embodiment, the UA 110 may forward uplink data to the relay node102 via the access link 108. Typically, the distance between the UA 110and the relay node 102 may be less than the distance between the relaynode 102 and the access node 106. Because of shorter distance betweenthe UA 110 and the relay node 102, this link may have a highersignal-to-interference ratio (SINR). Further, the shorter distance mayalso have less path loss in comparison to the distance between the relaynode 102 and the access node 106. For example, the relation between thepath loss L in decibel (dB) and the distance R may be obtained using thefollowing expression or equation:L=140.7+36.7 log ₁₀ R.According to this relation, it is clear that reducing the distance Rreduces the path loss L. For example, if the distance between the UA 110and the relay node 102 is ten times smaller than the distance betweenthe relay node 102 and the access node 106, the path loss associatedwith the access link 108 may be about 36.7 dB less than the path lossassociated with the relay link 104. Hence, the transmission power forthe access link 108 may also be smaller by about 36.7 dB than thetransmission power required for the relay link 104 to receive thecorresponding signals at about equal strength. The lower transmissionpower for the access link 108 may save more battery power at the UA 110.

The higher SINR and lower path loss associated with the access link 108may be suitable for using an OFDMA scheme to establish the uplinkbetween the UA 110 and the relay node 102 and transmit the uplink data.In this case, the uplink resource may also be established using lowerlayer signaling, such layer 1 signaling. Using the OFDMA, a subset ofsubcarriers or resources may be allocated to the UA 110. The subset ofsubcarriers may comprise discontinuous resources, continuous resources,or combinations thereof, which may improve resource utilization andnetwork efficiency. The UA 110 may obtain the allocated resources or thesubset of subcarriers over the PDCCH from the relay node 102 or theaccess node 106. For instance, the PDCCH may comprise an uplink grantthat includes the allocated resources. In some embodiments, a similarOFDMA scheme may be used to establish an uplink on the direct linkbetween the UA 110 and the access node 106 and transmit uplink data.

In an embodiment, the uplink grant may be forwarded in the form of abitmap of the allocated resources. For instance, the bitmap may comprisea plurality of bits that may be set to indicate a plurality of assignedRBs, which may be discontinuous. Alternatively, the bits may be set toindicate a plurality of assigned subsets of RBs or lists of RBs, whichmay each comprise a plurality of continuous RBs. In some embodiments,the UA 110 may receive a plurality of bitmaps that indicate individualRBs as well as lists of continuous RBs.

In another embodiment, a plurality of continuous subsets of assignedresources or RBs may be transported over the PDCCH by signaling thefirst and last RB for each subset. In yet another embodiment, theassigned RBs may be forwarded over the PDCCH using a DCI format, such asa DCI format 1, 1A, 2, or 2A, as specified in the 3GPP TS 36.212.

FIG. 2 illustrates an embodiment of a method 200 for establishing anuplink relay link in the wireless communication system 100 to providethe MIMO feedback and configuration information. In block 210, the relaynode 102 may establish an uplink with the access node 106 using higherlayer signaling. The uplink may be used to transport the MIMO feedbackinformation, configuration information, or both from the relay node 102to the access node 106. For instance, the relay node 102 may signal theaccess node 106 using the RRC protocol to provide the MIMO feedbackand/or configuration information. The MIMO feedback and/or configurationinformation may be provided when necessary in a periodic manner or uponrequest from the access node 106. Accordingly, the values or precodingvalues of the feedback and/or configuration information may be providedover the uplink.

FIG. 3 illustrates an embodiment of a method 300 for establishing anuplink access link in the wireless communication system 100 to forwardthe uplink data. In block 310, the UA 110 may receive an uplink grantincluding a plurality of allocated subcarriers or resources for OFDMA.For instance, the UA 110 may receive the uplink grant over a PDCCH fromthe relay node 102 or the access node 106. For instance, the uplink mayinclude at least one bitmap comprising the allocated individual RBs,lists of continuous RBs, or both. Alternatively, the uplink may comprisea DCI format 1, 1A, 2, or 2A that indicates the allocated resources. Inblock 320, the UA 110 may establish an uplink with the relay node 102using OFDMA and the allocated resources. The uplink may be used totransport the uplink data from the UA 110 to the relay node 102. Forinstance, the UA 102 may send communications data to the relay node 102using layer 1 signaling and the subcarriers or resources allocated tothe UA 110.

The UA 110 and other components described above might include aprocessing component that is capable of executing instructions relatedto the actions described above. FIG. 4 illustrates an example of asystem 700 that includes a processing component 710 suitable forimplementing one or more embodiments disclosed herein. In addition tothe processor 710 (which may be referred to as a central processor unitor CPU), the system 700 might include network connectivity devices 720,random access memory (RAM) 730, read only memory (ROM) 740, secondarystorage 750, and input/output (I/O) devices 760. These components mightcommunicate with one another via a bus 770. In some cases, some of thesecomponents may not be present or may be combined in various combinationswith one another or with other components not shown. These componentsmight be located in a single physical entity or in more than onephysical entity. Any actions described herein as being taken by theprocessor 710 might be taken by the processor 710 alone or by theprocessor 710 in conjunction with one or more components shown or notshown in the drawing, such as a DSP 502. Although the DSP 502 is shownas a separate component, the DSP 502 might be incorporated into theprocessor 710.

The processor 710 executes instructions, codes, computer programs, orscripts that it might access from the network connectivity devices 720,RAM 730, ROM 740, or secondary storage 750 (which might include variousdisk-based systems such as hard disk, floppy disk, or optical disk).While only one CPU 710 is shown, multiple processors may be present.Thus, while instructions may be discussed as being executed by aprocessor, the instructions may be executed simultaneously, serially, orotherwise by one or multiple processors. The processor 710 may beimplemented as one or more CPU chips.

The network connectivity devices 720 may take the form of modems, modembanks, Ethernet devices, universal serial bus (USB) interface devices,serial interfaces, token ring devices, fiber distributed data interface(FDDI) devices, wireless local area network (WLAN) devices, radiotransceiver devices such as code division multiple access (CDMA)devices, global system for mobile communications (GSM) radio transceiverdevices, worldwide interoperability for microwave access (WiMAX)devices, and/or other well-known devices for connecting to networks.These network connectivity devices 720 may enable the processor 710 tocommunicate with the Internet or one or more telecommunications networksor other networks from which the processor 710 might receive informationor to which the processor 710 might output information. The networkconnectivity devices 720 might also include one or more transceivercomponents 725 capable of transmitting and/or receiving data wirelessly.

The RAM 730 might be used to store volatile data and perhaps to storeinstructions that are executed by the processor 710. The ROM 740 is anon-volatile memory device that typically has a smaller memory capacitythan the memory capacity of the secondary storage 750. ROM 740 might beused to store instructions and perhaps data that are read duringexecution of the instructions. Access to both RAM 730 and ROM 740 istypically faster than to secondary storage 750. The secondary storage750 is typically comprised of one or more disk drives or tape drives andmight be used for non-volatile storage of data or as an over-flow datastorage device if RAM 730 is not large enough to hold all working data.Secondary storage 750 may be used to store programs that are loaded intoRAM 730 when such programs are selected for execution.

The I/O devices 760 may include liquid crystal displays (LCDs), touchscreen displays, keyboards, keypads, switches, dials, mice, track balls,voice recognizers, card readers, paper tape readers, printers, videomonitors, or other well-known input devices. Also, the transceiver 725might be considered to be a component of the I/O devices 760 instead ofor in addition to being a component of the network connectivity devices720. Some or all of the I/O devices 760 may be substantially similar tovarious components depicted in the previously described drawing of theUA 110, such as the display 402 and the input 404.

The following are incorporated herein by reference for all purposes:3GPP TS 36.212, 3GPP TS 36.304, and 3GPP TS 36.331.

In an embodiment, a method is provided for providing MIMO feedbackinformation and configuration information. The method includestransporting the feedback information, configuration information, orboth over an uplink relay link using higher layer signaling.

In an embodiment, the method for providing MIMO feedback information andconfiguration information further comprising using higher ordermodulation to transmit the feedback information, configurationinformation, or both over the uplink relay link.

In an embodiment, the method for providing MIMO feedback information andconfiguration information, wherein the feedback information,configuration information, or both is transmitted over the uplink relaylink using 256 QAM or higher modulation orders.

In another embodiment, a method is provided for providing uplink datatransmission over an access link. The method includes transporting theuplink data over an uplink access link using OFDMA.

In another embodiment, a relay node is provided. The relay node includesa processor configured to promote transmitting MIMO feedbackinformation, configuration information, or both over an uplink relaylink using higher layer signaling.

In another embodiment, a UA is provided. The UA includes a processorconfigured to promote transmitting uplink data over an uplink accesslink using OFDMA.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

Also, techniques, systems, subsystems and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component, whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. A method for transmitting uplink data by a useragent, comprising: establishing an uplink access link with a relay nodethat has a relay link to an access device, wherein the uplink accesslink utilizes an orthogonal frequency-division multiplexing (OFDM)access scheme between the user agent and the relay node regardless ofthe access scheme used between the relay node and the access device; andtransmitting OFDM physical layer feedback to the relay node via theuplink access link, wherein the uplink access link is established usinglayer 1 signaling, and wherein the relay link is established usinghigher layer signaling, the higher layer signaling being higher thanlayer 1 signaling, wherein feedback information is transported morefrequently to the relay node via the uplink access link as compared tofeedback information transported to the access device via the relaylink, wherein the feedback information transported to the relay nodecomprises the OFDM physical layer feedback.
 2. The method of claim 1,wherein a distance from the user agent to the relay node issubstantially less than a distance from the relay node to the accessdevice.
 3. The method of claim 1 further comprising: obtaining a subsetof assigned OFDM resources that are used to transport the OFDM physicallayer feedback.
 4. The method of claim 3, wherein the subset of assignedOFDM resources is obtained over a physical downlink control channel(PDCCH).
 5. The method of claim 3, wherein the subset of assigned OFDMresources is indicated using a bitmap of assigned individual resourceblocks.
 6. The method of claim 5, wherein the assigned resource blocksare discontinuous.
 7. The method of claim 3, wherein the subset ofassigned OFDM resources is indicated using the first and last resourceblock for each assigned subset of continuous resource blocks.
 8. Themethod of claim 3, wherein the subset of assigned OFDM resources isindicated using at least one of a downlink control information (DCI)format 1, DCI format 1A, DCI format 2, and DCI format 2A.
 9. The methodof claim 1, wherein the uplink access link between the user agent andthe relay node is a Multiple-Input Multiple-Output (MIMO) connection,and the OFDM physical layer feedback includes MIMO feedback information.10. The method of claim 2, wherein path loss between the user agent andthe relay node is substantially less than path loss between the relaynode and the access device.
 11. The method of claim 1, furthercomprising using lower order modulation to transmit data over the uplinkaccess link, the lower order modulation being lower than modulationrates used to transmit data over the relay link.
 12. A user agent (UA)comprising: a processor configured to promote establishing an uplinkaccess link with a relay node that has a relay link to an access device,wherein the uplink access link utilizes an orthogonal frequency-divisionmultiplexing (OFDM)scheme between the user agent and the relay noderegardless of the access scheme used between the relay node and theaccess device; and the processor further configured to promotetransmitting OFDM physical layer feedback to the relay node via theuplink access link, wherein the uplink access link is established usinglayer 1 signaling, and wherein the relay link is established usinghigher layer signaling, the higher layer signaling being higher thanlayer 1 signaling, wherein feedback information is transported morefrequently to the relay node via the uplink access link as compared tofeedback information transported to the access device via the relaylink, wherein the feedback information transported to the relay nodecomprises the OFDM physical layer feedback.
 13. The UA of claim 12,wherein a distance associated with the uplink access link issubstantially less than a distance associated with a direct link. 14.The UA of claim 12, wherein the processor is further configured toobtain a subset of assigned OFDM resources that are used to transportfeedback information, configuration information, or both.
 15. The UA ofclaim 14, wherein the subset of assigned OFDM resources is obtained overa physical downlink control channel (PDCCH).
 16. The UA of claim 14,wherein the subset of assigned OFDM resources is indicated using abitmap of assigned individual resource blocks.
 17. The UA of claim 16,wherein the assigned resource blocks are discontinuous.
 18. The UA ofclaim 14, wherein the subset of assigned OFDM resources is indicatedusing the first and last resource block for each assigned subset ofcontinuous resource blocks.
 19. The UA of claim 14, wherein the subsetof assigned OFDM resources is indicated using at least one of a downlinkcontrol information (DCI) format 1, DCI format 1A, DCI format 2, and DCIformat 2A.
 20. The UA of claim 13, wherein path loss associated with theuplink access link is substantially less than path loss associated withthe direct link.
 21. The method of claim 1, further comprising usinglayer 1 signaling to transmit the OFDM physical layer feedback.
 22. TheUA of claim 12, wherein the processor is further configured to promoteusing layer 1 signaling to transmit the OFDM physical layer feedback.23. The UA of claim 12, wherein the processor is further configured topromote using lower order modulation to transmit data over the uplinkaccess link, the lower order modulation being lower than modulationrates used to transmit data over the relay link.